1. Field of the Invention
The present invention relates to novel calcium-binding proteins, DNA encoding them, antibodies against the calcium-binding proteins, hybridomas producing the antibodies, diagnostic agents comprising the antibodies, etc.
2. Related Art
Extracellular calcium ion concentration is known to play a role in the regulation of cellular proliferation and differentiation. On the other hand, intracellular calcium ion is one of the key transfer factors for intracellular signal transduction. The calcium signals are transduced by various calcium-binding proteins (CaBP). Calcium-binding proteins are largely classified as those with the EF-hand motif, such as calmodulin, troponin C, the S100 protein family, etc. and those without EF-hands, such as the anexine family. These are presumed to carry out separate and important physiological roles, but their physiological roles have not been completely elucidated.
Calmodulin mediates many calcium ion-dependent cellular reactions, and it is understood to be a ubiquitus CaBP required during mitosis. In contrast, CaBPs of the S100 protein family are expressed specifically according to cell cycle or cell type, and they are implicated in specific signal transduction for cellular division and differentiation. The S100 protein family includes S100.alpha., S100.beta., calcyclin, MRP8, MRP14, etc., each of which have 2 EF-hand motifs.
Thus, the study of the presence and function of CaBPs is crucial for understanding the mechanisms of cell proliferation and differentiation, and is expected to yield useful knowledge for the understanding, diagnosis and treatment of the related diseases.